My #8 goes bye bye and who know's why - OP runs and hides

[Mach1Marauder]

Shouldn't you be knock free?
Especially with a lund tune.

Pretty much, but they are talking about an aggressive tune.

 

[DarkTrak]

my 93 aggressive tune knocks a decent bit at WOT up around 5500, but in fairness I did my logging during 100F temps.

Its going to cool down next week, so I'll do it again.

I'm buying some VP100 Unleaded gas to mix in when I go to the track. Figure a few gallons of 100 to 93, should get me around 94-95'ish, which should at least ensure my minimum octane is 93 during these warmer months.

Dont do the "should get me" method. Do the math. 16 gallon tank right? So, figure 8 gallons of 93 and 8 gallons of 100(just as an example)

[(8 * 93) + (8 * 100)] / 16 = octane rating
744 + 800 / 16 = 96.5

so:

new octane rating is 96.5 octane.
16 is total gallons used.

Make sense?

 

[Seer]

Dont do the "should get me" method. Do the math. 16 gallon tank right? So, figure 8 gallons of 93 and 8 gallons of 100(just as an example)

[(8 * 93) + (8 * 100)] / 16 = octane rating
744 + 800 / 16 = 96.5

so:

new octane rating is 96.5 octane.
16 is total gallons used.

Make sense?

Perfect sense, except i dont run with a full tank at the drag strip. So, cut your figures in half, or by 25-30%. Weight savings

The goal is to ensure 93 minimum (94-95 safe zone). You need to go in there and just assume for the worst and say that when I goto my local BP pump, and push the 93 button, I'm getting 91. <Insert paranoia here>

I know, it's not probable, but I see throwing in enough to make 91 = at least 94. Cheap insurance for track days.

I wish sunoco still supplied 94 octane.

 

[BAKnBLK2010]

my 93 aggressive tune knocks a decent bit at WOT up around 5500, but in fairness I did my logging during 100F temps.

Its going to cool down next week, so I'll do it again.

I'm buying some VP100 Unleaded gas to mix in when I go to the track. Figure a few gallons of 100 to 93, should get me around 94-95'ish, which should at least ensure my minimum octane is 93 during these warmer months.

With the knock you are getting couldn't you just go in and pull maybe 2 degrees of global timing? I noticed in my Lund tunes he leaves the global timing open so we can make adjustments.

 

[DarkTrak]

With the knock you are getting couldn't you just go in and pull maybe 2 degrees of global timing? I noticed in my Lund tunes he leaves the global timing open so we can make adjustments.

Thats what he told me to do if I wanted to DD my Agressive 93 tune.

 

[beefcake]

With the knock you are getting couldn't you just go in and pull maybe 2 degrees of global timing? I noticed in my Lund tunes he leaves the global timing open so we can make adjustments.

the car will do it itself

example, when i was trying out the new blower, i pulled 4 degrees of timing, car only ran 2 less than it was previously seeing, i added 2, it kept it where it was the previous run

assuming it's tuned correctly, it's going to adjust for you

 

[DarkTrak]

the car will do it itself

Then why did John suggest I do it MYSELF...?

 

[Seer]

Shouldn't you be knock free?
Especially with a lund tune.

I think it is more the weather playing havoc with the knock and timing retard. It's been very hot and humid here the past month. Way above normal. My BAMA tunes are doing the same thing.

With the knock you are getting couldn't you just go in and pull maybe 2 degrees of global timing? I noticed in my Lund tunes he leaves the global timing open so we can make adjustments.

I could, and most likely should. Although I live in Western, PA. We're in the middle of a vast heat wave, which I feel is attributed to this timing being pulled.

My BAMA 93R and 93P tunes are also knocking the same amounts and seeing similar timing pulls. As of right now, I am chalking this up to mid 90s to low 100s heat with high humidity. Not shoddy tuning.

If I want to play, I am going to have to run some 100 octane unleaded race gas

 

[BAKnBLK2010]

Well I'm in Ky and it's hotter than the gates of hell here right now too. You think taking out 3 degrees would be too much? That's what I'm thinking about doing.

 

[Seer]

Well I'm in Ky and it's hotter than the gates of hell here right now too. You think taking out 3 degrees would be too much? That's what I'm thinking about doing.

I don't feel its too much. I'm trying to negate the need to do it by ensuring there is a minimum octane level. I am thinking though no matter how much I run, I will still need to do a timing reduction until temperatures subside.

 

[Bmr4life]

the car will do it itself

example, when i was trying out the new blower, i pulled 4 degrees of timing, car only ran 2 less than it was previously seeing, i added 2, it kept it where it was the previous run

assuming it's tuned correctly, it's going to adjust for you

Relying on the car to do it itself could be part of the reason #8's are popping.

 

[UltraKla$$ic]

If you're having knock beyond adaptive learnings capabilities.................tune = suck

 

[19COBRA93]

If the car needs to pull timing on its own to correct knocking, the initial timing sounds too high. I wouldn't rely on the car to correct for something that should have been correct to begin with.

Dial that tune in to zero knock, period. That way in extreme situations (temp, load, etc), it can then do what it needs to do to save the motor. You can run a tune on the edge like that with forged pistons, but not these.

 

[beefcake]

Relying on the car to do it itself could be part of the reason #8's are popping.

when we added the new blower to the car, i did some datalogging on the track,

car went lean compared to where it was normally at, i needed to bump up base fuel pressure, the car pulled from 22 to 12 degrees of timing at wot to compensate for the knock

this is at around 750 rwhp

edit
upped base f/p by 10 psi, and timing and a/f went right back where it should be

 

[Bmr4life]

when we added the new blower to the car, i did some datalogging on the track,

car went lean compared to where it was normally at, i needed to bump up base fuel pressure, the car pulled from 22 to 12 degrees of timing at wot to compensate for the knock

this is at around 750 rwhp

edit
upped base f/p by 10 psi, and timing and a/f went right back where it should be

You were already running lower timing due to your car being FI. For NA applications, we should not be relying on the car to make a tune safe. It needs to made safe from the start.

 

[19COBRA93]

when we added the new blower to the car, i did some datalogging on the track,

car went lean compared to where it was normally at, i needed to bump up base fuel pressure, the car pulled from 22 to 12 degrees of timing at wot to compensate for the knock

this is at around 750 rwhp

edit
upped base f/p by 10 psi, and timing and a/f went right back where it should be

You've also melted down a motor. Maybe you should look at doing things a little differently.

 

[jsnyng]

I don't feel its too much. I'm trying to negate the need to do it by ensuring there is a minimum octane level. I am thinking though no matter how much I run, I will still need to do a timing reduction until temperatures subside.

I'm doing the same thing as you. I've got a 3-day autocross event this weekend where it is going to be 95+ degrees ambient with 115+ on the course.

Have you priced the gas in your area? VP100 is ~$50 for 5 gal and MS109 is ~$60 for 5 gal here in Atlanta.

 

[beefcake]

You've also melted down a motor. Maybe you should look at doing things a little differently.

wow, thats brilliant,

also had a bad o2 extender as well that wasn't reading a/f but thanks for looking

 

[BAKnBLK2010]

You've also melted down a motor. Maybe you should look at doing things a little differently.

The motor melt down wasn't a tuning issue. It was due to a faulty 02 extension that came with his headers. The car leaned way out in a pass and all went to hell from there. Terry is a pretty smart guy and knows what he's talking about.

 

[Bmr4life]

The motor melt down wasn't a tuning issue. It was due to a faulty 02 extension that came with his headers. The car leaned way out in a pass and all went to hell from there. Terry is a pretty smart guy and knows what he's talking about.

Yeah, I remember reading that from either March or April. Not a tuning issue at all. Was crazy though.